It is known that long drives in a motor car are tiring. Over time a driver's concentration level drops. A decline in concentration may lead to potentially hazardous traffic situations not being recognized or judged correctly. Also traffic situations may be misinterpreted leading to the wrong reaction as regards car control.
Fatigue warning systems are known from the art, which assess the alertness of a driver using a variety of criteria. Among others it is known to detect and electronically evaluate eye, pupil and/or eyelid movements of the driver by means of cameras, and on this basis to draw conclusions as to the driver's state of alertness. A warning can then be emitted in the form of an acoustic signal, a graphical display or vibration of a vehicle interface e.g. the steering wheel.
Furthermore, modern vehicles are frequently equipped with driver assistance systems. Such driver assistance systems may, for example, include an automatic longitudinal speed regulation, frequently called adaptive cruise control, which is capable of automatically maintaining the distance to the preceding motor vehicle. To this end, the assistance system may interact alternately with the accelerator and the brake. Also lane assist systems are frequently installed in current motor vehicles. Lane assistance systems prevent the vehicle from inadvertently leaving the lane by interfering with the steering mechanism. These systems too are contributors to safety.
The afore-mentioned systems ease the burden on the driver, but may contribute to the driver not maintaining his situational awareness of the current traffic conditions on the road.
For some time now work has been going on to develop motor vehicles which are operated completely automatically. Such motor vehicles are intended to drive from a current location of the motor vehicle to a target location without any intervention on the part of the driver, wherein dangerous situations are automatically detected.
It is, however, feasible that for safety reasons in extreme situations, control of the motor vehicle is to be handed over to the driver. It is also feasible that automatic driving could be restricted to certain zones and would not be permitted outside these zones. In urban regions, for example, where the number of road users of all categories is high including motor vehicle drivers, cyclists, pedestrians etc., automatic driving could be prohibited. Then it must be ensured that even with motor vehicles equipped with such automatic systems, drivers must always be in control in such zones.
During times in which the vehicle drives autonomously, the driver of the motor vehicle may occupy himself with other things. For example, a driver might read, listen to music, watch a film or make a telephone call. While such activities are going on, the driver might not pay attention to what is happening on the road. If, however, the driver has to assume control of the motor vehicle, for example when the driver is approaching a self-drive zone or is about to enter a potentially hazardous situation, he or she must be alerted to this fact. Depending on the current activity of the driver, it may take a certain amount of time until he or she has concentrated attention on the traffic and becomes aware of the situation before he or she can take over control of the motor vehicle. Therefore, a warning must be issued in advance in good time.